The present invention relates to methods for treating human and animal skins to expand said skins.
The skin is composed of an epidermis and a dermis. The dermis is composed collagen and elastin fibers as well as other components. The elastin fibers act like springs, and thus impart to skin its elastic recoil. Broken or destroyed elastin fibers can be found in the following conditions:
(a) The aging process: the skin of aged people is wrinkled because of the high percentage of broken elastin fibers, which prevents the skin from retaining its tautness.
(b) Cutis Laxa disease: this is a genetic disease in which elastin fibers are destroyed during adolescence, causing the skin of teenagers to wrinkle and giving them the appearance of old age.
U.S. Pat. No. 4,645,668 describes a method for the prevention and treatment of scars by repeatedly injecting collagenase into various types of disfiguring lesions (keloid, hypertrophic scars, disfiguring surgical scars, acne scars, and fibrotic bands). Therapy was discontinued when the scar appearance was satisfactory.
U.S. Pat. No. 4,276,281 describes the use of elastase in the form of an ointment to promote the healing of skin burns in rats. Application of the ointment hastened the removal of the burn eschar.
The disclosures of all references mentioned above and throughout the present specification are hereby incorporated herein by reference.
The present invention seeks to provide an improved method for expanding skin.
There is thus provided in accordance with a preferred embodiment of the present invention a method for expanding healthy skin, comprising administering to healthy skin an efficacious amount of an enzyme which cleaves elastin fibers. In a preferred embodiment of the invention, the enzyme is elastase or an elastase derivative.
In one preferred embodiment of the invention, the enzyme is administered by injection. In another preferred embodiment of the invention, the enzyme is administered by topical application. Preferably, the enzyme is administered in an concentration selected from (a) a concentration of at least 1 unit of activity per cm2 of skin or (b) a concentration of at least 1 mg of enzyme per cm2 of skin.
In a preferred embodiment of the invention, the healthy skin is adjacent to an area of skin which suffers from a condition or deficiency. In on preferred embodiment, the condition or deficiency is selected from the group consisting of: (a) skin loss after excision of a skin tumor or excision of necrotic skin; (b) trauma; (c) a congenital condition; and (d) a condition which has resulted or is likely to result in skin loss.
In another preferred embodiment of the present invention, the healthy skin is adjacent to an area of skin which is to undergo reconstructive surgery.
There is also provided, in accordance with a preferred embodiment of the invention, a method for increasing the surface area of a piece of skin to be applied as a skin graft, comprising contacting the piece of skin with an efficacious amount of an enzyme which cleaves elastin fibers. In a preferred embodiment of the invention, the enzyme is elastase or an elastase derivative.
In one preferred embodiment of the invention, the piece of skin is contacted with the enzyme by injecting the enzyme into the piece of skin. In another preferred embodiment of the invention, the piece of skin is contacted with the enzyme by topically applying the enzyme to the piece of skin. In yet another preferred embodiment of the invention, the piece of skin is contacted with the enzyme by soaking the piece of skin in a solution containing the enzyme.
There is also provided, in accordance with a preferred embodiment of the invention, a method for increasing the yield of leather from an animal, comprising contacting the hide of the animal or a portion thereof with an efficacious amount of an enzyme which cleaves elastin fibers. In a preferred embodiment of the invention, the enzyme is elastase or an elastase derivative.
In one preferred embodiment of the invention, the hide or portion thereof is on a live animal. In another preferred embodiment of the invention, the hide or portion thereof has been removed from the animal but has not yet been cured or tanned.
In one preferred embodiment of the invention, the hide or portion thereof is contacted with the enzyme by injecting the enzyme into the hide or portion thereof. In another preferred embodiment of the invention, the hide or portion thereof is contacted with the enzyme by topically applying the enzyme to the hide or portion thereof. In yet another preferred embodiment of the invention, the hide or portion thereof is contacted with the enzyme by soaking the hide or portion thereof in a solution containing the enzyme.
There is also provided, in accordance with a preferred embodiment of the invention, an animal hide or portion thereof which has been expanded by contacting said hide or portion thereof with an efficacious amount of an enzyme which cleaves elastin fibers.
There is also provided, in accordance with a preferred embodiment of the invention, a method for imitating in a person with healthy skin the pathological condition of the skin of a person suffering from Cutis Laxa disease, comprising administering to a region of healthy skin of said person in which region it is desired to imitate said pathological condition an efficacious amount of an enzyme which cleaves elastin fibers.
There is also provided, in accordance with a preferred embodiment of the invention, a method for decreasing the elastic resistance of skin to pulling, comprising administering to said skin an efficacious amount of an enzyme which cleaves elastin fibers.